Users can communicate with each other in a number of different ways using MU systems:

• Text-based chat (maybe with speech synthesis
• Audio streaming
• Video streaming

Restricting communication

• May distinguish between 'performers' and 'observers' (e.g. virtual theatre or a virtual lecture)
• Communication usually restricted to users within the same zone/location
• Communication may be restricted to users (avatars) in close proximity to each other
• Most systems permit private one-to-one communication between avatars

Deep Matrix in action, showing the multi-user virtual world, an avatar and the chat console, with list of users and a pop-up menu for choosing gestures: